Implement simple setting of link state and IP addresses

meson.build

@@ -1,6 +1,8 @@
 project('neco', 'c', default_options : ['c_std=gnu11'])
 
 cc = meson.get_compiler('c')
-ubox_dep = cc.find_library('ubox')
+libubox_dep = cc.find_library('ubox')
+
+libmnl_dep = dependency('libmnl', method : 'pkg-config')
 
 subdir('src')

src/config-load.c

@@ -120,8 +120,14 @@ bool read_config(const char *path) {
 	free(subtypes);
 
 	device_t *dev, *tmp;
+	avl_for_each_element(devices, dev, node)
+		dev->type->init(dev);
+
+	//avl_for_each_element(devices, dev, node)
+	//	dev->type->release(dev);
+
 	avl_remove_all_elements(devices, dev, node, tmp)
-		dev->type->free_device(dev);
+		dev->type->free(dev);
 
 	free(devices);
 

src/device-interface.c

@@ -1,17 +1,23 @@
 #include "device.h"
 #include "keywords.h"
+#include "netlink.h"
 #include "util.h"
 #include "vector.h"
 
-#include <arpa/inet.h>
-#include <netinet/ether.h>
-#include <netinet/in.h>
-
 #include <assert.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <netinet/ether.h>
+#include <netinet/in.h>
+
+#include <linux/if.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
 static device_type_t device_type_interface;
 
 typedef struct _ipaddr {
@@ -144,7 +150,7 @@ static bool process_section_static(device_interface_t *iface, const ini_section_
 	return true;
 }
 
-static void interface_free_device(device_t *dev) {
+static void interface_free(device_t *dev) {
 	device_interface_t *iface = container_of(dev, device_interface_t, device);
 
 	VECTOR_FREE(iface->addrs);
@@ -152,6 +158,129 @@ static void interface_free_device(device_t *dev) {
 	free(iface);
 }
 
+static bool interface_set_link_flags(unsigned index, unsigned change, unsigned flags) {
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+
+	struct mnl_socket *nl = nl_socket();
+
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= RTM_SETLINK;
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	int seq = nlh->nlmsg_seq = nl_seq();
+
+	struct ifinfomsg *ifi = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifi));
+	ifi->ifi_index = index;
+	ifi->ifi_family = AF_UNSPEC;
+
+	ifi->ifi_change = change;
+	ifi->ifi_flags = flags;
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		return false;
+	}
+
+	int ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	if (ret == -1) {
+		perror("mnl_socket_recvfrom");
+		return false;
+	}
+
+	ret = mnl_cb_run(buf, ret, seq, mnl_socket_get_portid(nl), NULL, NULL);
+	if (ret == -1) {
+		perror("mnl_cb_run");
+		return false;
+	}
+
+	return true;
+}
+
+static bool interface_set_link_state(unsigned index, bool up) {
+	return interface_set_link_flags(index, IFF_UP, up ? IFF_UP : 0);
+}
+
+static bool interface_set_ipaddr(unsigned index, ipaddr_prefix_t *addr, bool add) {
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+
+	struct mnl_socket *nl = nl_socket();
+
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= add ? RTM_NEWADDR : RTM_DELADDR;
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	if (add)
+		nlh->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+
+	int seq = nlh->nlmsg_seq = nl_seq();
+
+	struct ifaddrmsg *ifa = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifa));
+	ifa->ifa_index = index;
+	ifa->ifa_family = addr->addr.af;
+
+	ifa->ifa_prefixlen = addr->plen;
+
+	switch (addr->addr.af) {
+	case AF_INET:
+		mnl_attr_put(nlh, IFA_LOCAL, 4, &addr->addr.addr4);
+		break;
+
+	case AF_INET6:
+		mnl_attr_put(nlh, IFA_LOCAL, 16, &addr->addr.addr6);
+		break;
+
+	default:
+		errno = EINVAL;
+		return false;
+	}
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		return false;
+	}
+
+	int ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	if (ret == -1) {
+		perror("mnl_socket_recvfrom");
+		return false;
+	}
+
+	ret = mnl_cb_run(buf, ret, seq, mnl_socket_get_portid(nl), NULL, NULL);
+	if (ret == -1) {
+		perror("mnl_cb_run");
+		return false;
+	}
+
+	return true;
+}
+
+static void interface_init(device_t *dev) {
+	device_interface_t *iface = container_of(dev, device_interface_t, device);
+
+	unsigned index = if_nametoindex(NODE_NAME(dev));
+	if (!index)
+		return;
+
+	interface_set_link_state(index, true);
+
+	for (size_t i = 0; i < VECTOR_LEN(iface->addrs); i++)
+		interface_set_ipaddr(index, &VECTOR_INDEX(iface->addrs, i), true);
+}
+
+static void interface_update(device_t *dev) {
+}
+
+static void interface_release(device_t *dev) {
+	device_interface_t *iface = container_of(dev, device_interface_t, device);
+
+	unsigned index = if_nametoindex(NODE_NAME(dev));
+	if (!index)
+		return;
+
+	for (size_t i = 0; i < VECTOR_LEN(iface->addrs); i++)
+		interface_set_ipaddr(index, &VECTOR_INDEX(iface->addrs, i), false);
+
+	interface_set_link_state(index, false);
+}
+
 static device_t * interface_process_config(const char *name, const ini_file_t *config) {
 	device_interface_t *iface = calloc(1, sizeof(*iface));
 	if (!iface)
@@ -187,13 +316,17 @@ static device_t * interface_process_config(const char *name, const ini_file_t *c
 	return dev;
 
 err:
-	interface_free_device(dev);
+	interface_free(dev);
 	return NULL;
 }
 
 static device_type_t device_type_interface = {
 	.process_config = interface_process_config,
-	.free_device = interface_free_device,
+	.free = interface_free,
+
+	.init = interface_init,
+	.update = interface_update,
+	.release = interface_release,
 };
 
 __attribute__((constructor))

src/device.h

@@ -16,7 +16,11 @@ typedef struct _device {
 struct _device_type {
 	struct avl_node node;
 	device_t * (*process_config)(const char *name, const ini_file_t *config);
-	void (*free_device)(device_t *device);
+	void (*free)(device_t *device);
+
+	void (*init)(device_t *device);
+	void (*update)(device_t *device);
+	void (*release)(device_t *device);
 };
 
 void register_device_type(const char *name, device_type_t *device_type);

src/meson.build

@@ -7,7 +7,13 @@ src = [
 	'device-bridge.c',
 	'device-interface.c',
 	'keywords.c',
+	'netlink.c',
 	'vector.c',
 ]
 
-executable('neco', sources: src, dependencies: [ubox_dep])
+dep = [
+	libubox_dep,
+	libmnl_dep,
+]
+
+executable('neco', sources: src, dependencies: dep)

src/neco.c

@@ -1,6 +1,13 @@
 #include "config-load.h"
+#include "netlink.h"
 
 int main(int argc, char *argv[]) {
+	if (!nl_init())
+		return 1;
+
 	read_config(argv[1]);
+
+	nl_deinit();
+
 	return 0;
 }

src/netlink.c

@@ -0,0 +1,38 @@
+#include "netlink.h"
+
+#include <stdio.h>
+
+static struct mnl_socket *nl;
+static uint32_t seq;
+
+bool nl_init(void) {
+	nl = mnl_socket_open(NETLINK_ROUTE);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		return false;
+	}
+
+	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		nl_deinit();
+		return false;
+	}
+
+	return true;
+}
+
+void nl_deinit(void) {
+	if (!nl)
+		return;
+
+	mnl_socket_close(nl);
+	nl = NULL;
+}
+
+struct mnl_socket * nl_socket(void) {
+	return nl;
+}
+
+uint32_t nl_seq(void) {
+	return seq++;
+}

src/netlink.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <libmnl/libmnl.h>
+
+#include <stdbool.h>
+#include <stdbool.h>
+
+bool nl_init(void);
+void nl_deinit(void);
+
+struct mnl_socket * nl_socket(void);
+uint32_t nl_seq(void);